Visible light absorbing film, structural body having the visible light absorbing film, and visible light absorbing ink for forming visible light absorbing film

ABSTRACT

The visible light absorbing film according to the present invention is formed by a visible light absorbing ink having been coated on one side or both sides of a substrate which has solar radiation reflecting properties and whose visible light reflectance is 10% or more, and is characterized in that the degree of reduction of visible light reflectance is 0.9 or less as defined by degree of reduction of visible light reflectance=[visible light reflectance (%) after coating of the ink]/[visible light reflectance (%) before coating of the ink], and the degree of reduction of solar radiation reflectance is 0.25 or more as defined by degree of reduction of solar radiation reflectance=[solar radiation reflectance (%) after coating of the ink]/[solar radiation reflectance (%) before coating of the ink].

TECHNICAL FIELD

This invention relates to a visible light absorbing film, a structuralmember having this visible light absorbing film, and a visible lightabsorbing ink which forms the visible light absorbing film. It relatesto a visible light absorbing film which is formed, e.g., on atransparent film having metallic luster on the surface of which film ametallic thin film has been formed or on a semitransparent substratemade of glass or the like so as to enable restraint of glaringness inthe visible region and also enables the above substrate to maintain evenits heat insulating properties, a structural member having this visiblelight absorbing film, and a visible light absorbing ink which forms thevisible light absorbing film.

BACKGROUND ART

Glass, transparent films and so forth on which shielding films have beenformed by coating, sputtering or the like method are conventionally usedfor the purpose of shielding the sunlight that enters through windowmaterials of constructions, window materials of automobiles, and soforth.

These shielding films are roughly grouped into a heat ray reflectiontype and a heat ray absorption type.

More specifically, many of the heat ray reflection type are metallicthin films of Al, gold or the like formed on transparent substrates suchas glass and transparent films by sputtering, ion plating, vacuumdeposition or the like method, as disclosed in, e.g., Japanese PatentApplication Laid-open No. S57-59749. Such metallic thin films reflectlight having wavelengths ranging from the visible region up to theinfrared region, and hence can make the substrate less rise intemperature and have very good heat insulating properties. Since,however, they also reflect light having wavelengths in the visibleregion, they have had a disadvantage that they are so glaring as to looklike mirrors and are unfavorable in view of design quality.

On the other hand, in the heat ray absorption type, substrates arecoated with, or kneaded therein with, such organic dyes or organicpigments as those disclosed in Japanese Patent Application Laid-open No.2000-80319, to color the substrates so as to shield the heat rays.Shielding films of this type are widely prevailing especially becausethe dyes are inexpensive and are easy to handle, but are disadvantageousin that they have poor weatherability. Also, shielding films of thistype can be free of any glaringness due to the reflection in the visibleregion and have superior design quality, but have had a disadvantagethat they have lower heat insulating efficiency than those of the heatray reflection type because the former inevitably allows the heat energyabsorbed in the substrates, to radiate into the interior. Still also,shielding films making use of the above organic dyes or organicpigments, or coloring materials such as oxides, sulfides or sulfates ofmetals, have had no properties that may achieve both high shieldingproperties and restraint of glaringness. Furthermore, they have had aproblem that, because of use of coloring materials, they have soexcessively bright color tone in many cases as to come into depthless orreposeless appearance.

The present invention has been made taking note of such problems.Accordingly, a subject of the present invention is to provide a visiblelight absorbing film which enables restraint of glaringness in thevisible region in the heat ray reflection type one and also enablessubstrates to maintain even their heat insulating properties, and toprovide a structural member having this visible light absorbing film,and a visible light absorbing ink which forms the visible lightabsorbing film.

Then, the present inventors have made extensive studies in order tosettle the above subject. As the result, they have come up with adiscovery that, where a visible light absorbing film is formed on atleast one side of a substrate having solar radiation reflectingproperties, using a visible light absorbing ink containing fineparticles which may selectively absorb the visible-region light andtransmit the near-infrared-region light and infrared-region light, onlythe visible-region light can selectively be absorbed as the substrate iskept to have its solar radiation reflecting properties, in virtue of theaction of the visible light absorbing film formed. The present inventionhas been accomplished on the basis of such a technical finding.

DISCLOSURE OF THE INVENTION

More specifically, the visible light absorbing film according to thepresent invention is formed by a visible light absorbing ink having beencoated on one side or both sides of a substrate which has solarradiation reflecting properties and whose visible light reflectance is10% or more, and is characterized in that:

-   -   the degree of reduction of visible light reflectance is 0.9 or        less as defined by degree of reduction of visible light        reflectance=[visible light reflectance (%) after coating of the        ink]/[visible light reflectance (%) before coating of the ink];        and    -   the degree of reduction of solar radiation reflectance is 0.25        or more as defined by degree of reduction of solar radiation        reflectance=[solar radiation reflectance (%) after coating of        the ink]/[solar radiation reflectance (%) before coating of the        ink].

According to the visible light absorbing film according to the presentinvention, having been formed on one side or both sides of thesubstrate, its degree of reduction of visible light reflectance of thefilm is 0.9 or less, and this reduces the reflection of visible lightfrom the substrate to enable restraint of glaringness in the visibleregion. Also, its degree of reduction of solar radiation reflectance is0.25 or more, and this retains the reflection of solar radiation fromthe substrate to enable the substrate to maintain even its heatinsulating properties.

Here, as the substrate, any desired material may be used as long as ithas solar radiation reflecting properties and has a visible lightreflectance of 10% or more, and may be exemplified by films, glasssheets, transparent resin sheets and so forth having such reflectioncharacteristics alone, films, glass sheets, transparent resin sheets andso forth on which metallic thin films have been formed, and compositemembers obtained by laminating the films, glass sheets, transparentresin sheets and so forth on which metallic thin films have been formed,to different films, glass sheets, transparent resin sheets and so forth.

In order that the substrate can maintain its clear translucency afterthe visible light absorbing film has been formed thereon, it is alsopreferable that, as a haze value measured according to JIS K 7105, thesubstrate on which the visible light absorbing film has been formed hasa haze value which has been made lower than the haze value beforeformation of the visible light absorbing film, or that the substrate onwhich the visible light absorbing film has been formed has a haze valuewhich has been made higher than the haze value before formation of thevisible light absorbing film and its gain is +3% or less.

In order that the visible light absorbing film having been formed hasnot so excessively bright color tone as to come into a depthless orreposeless state, it is further preferable that, as chromaticnessc*=[(a*)²+(b*)²]^(1/2) in the L*a*b* color system, the visible lightabsorbing film has a value of 40 or less.

The structural member having the visible light absorbing film accordingto the present invention is characterized in that a laminate formed byproviding the above visible light absorbing film on one side or bothsides of a substrate which has solar radiation reflecting properties andwhose visible light reflectance is 10% or more; the laminate beingincorporated directly or via an intervenient member or via a space.

The visible light absorbing ink according to the present invention ischaracterized by containing at least one fine particles of a compoundoxide selected from the group consisting of Cu—Fe—Mn, Cu—Cr, Cu—Cr—Mn,Cu—Cr—Mn—Ni, Cu—Cr—Fe and Co—Cr—Fe, titanium black, titanium nitride,titanium oxynitride, a dark-colored azo pigment, a perylene blackpigment, an aniline black pigment and carbon black; the fine particleshaving an average dispersed-particle diameter of 300 nm or less in theink.

BEST MODES FOR PRACTICING THE INVENTION

The present invention is described below more specifically and indetail.

First, the present invention makes use of a substrate having reflectionin the visible region or a substrate having metallic luster in thevisible region. The visible light absorbing ink is coated on at leastone side of this substrate to form the visible light absorbing film,thereby aiming at prevention of the glaringness in the visible region,which is a disadvantage the substrate has. Further, in order not todamage the heat insulating properties of the substrate as far aspossible, a material is selected which may selectively absorb lightperceivable by the human eye, in particular, visible light havingwavelengths in the region of from 380 nm to 780 nm, and may transmitlight having wavelengths in the near infrared region and infrared region(780 nm or more). This material is made into an ink, which is coated onone side or both sides of a heat ray reflection type substrate (i.e.,the substrate having solar radiation reflecting properties and having avisible light reflectance of 10% or more) to form the visible lightabsorbing film so as to enable constitution having less glaringness inthe visible region and having higher heat insulating efficiency than theheat ray absorption type.

More specifically, a heat ray reflection type heat insulating materialaccording to the present invention is one obtained by, e.g., coating thevisible light absorbing ink on one side or both sides of a metalvacuum-deposited substrate having the above reflection characteristics.The surface vacuum-deposited thereon with a metal causes reflection dueto its plasmons. Hence, it shows reflection characteristics over a widerange of from the ultraviolet region to the visible and infraredregions. Where the visible light absorbing ink is coated on the surfaceof this substrate, only light components in the visible region whichhave been reflected on the surface vacuum-deposited with a metal areabsorbed in the visible light absorbing film formed of the visible lightabsorbing ink, and hence the surface has no longer the glaringnesslooking like that of mirrors. As for the light in the near infraredregion and infrared region, it is transmitted through the visible lightabsorbing film and is sufficiently reflected at the film surfacevacuum-deposited with a metal. Hence, it is consequently possible tomaintain the high heat insulating properties the substrate has.

For example, where the visible light absorbing film is formed by coatingthe visible light absorbing ink on one side of a semitransparentsubstrate vacuum-deposited with a metal, the semitransparent substratemay be placed with its visible light absorbing film side outdoors. Thus,the visible light absorbing film absorbs visible light, and hence therecan be no unpleasant feeling due to glaringness on the outdoor side.Also, infrared rays coming from the outdoor side are transmitted throughthe visible light absorbing film and reflected at the metalvacuum-deposited surface, and hence the heat insulating properties canbe kept high. Further, where the visible light absorbing film is placedon the indoor side, the inside of a room can be kept from being mirroredin. On the outdoor side, the outdoor heat energy is reflected by thereflection taking place at the metal vacuum-deposited surface, and hencethe heat insulating properties of the semitransparent substratevacuum-deposited with a metal can be kept high. The visible lightabsorbing film may also be formed on both sides of the semitransparentsubstrate vacuum-deposited with a metal.

Since the visible light absorbing film having been formed may have soexcessively bright color tone as to come into a depthless br reposelessstate, its chromaticness c*=[(a*)²+(b*)²]^(1/2) in the L*a*b* colorsystem should be set a little lower, and may preferably be 40 or less.This is because, if the chromaticness c* is more than 40, the visiblelight absorbing film may have a hue which is so highly bright as to comeinto reposeless appearance. That is, where the chromaticness c* is 40 orless, the visible light absorbing film can have a pale and dull hue, andcan have appearance with depth and repose.

As to the material used in the visible light absorbing ink according tothe present invention and capable of selectively absorbing thevisible-region light, it may include the following substances.

For example, as an inorganic material, it may include a compound oxideselected from the group consisting of a Cu—Fe—Mn type, a Cu—Cr type, aCu—Cr—Mn type, a Cu—Cr—Mn—Ni type, a Cu—Cr—Fe and a Co—Cr—Fe type,titanium oxynitride, titanium nitride, lower-oxidized titanium oxide(titanium black) and carbon black. These materials have superiorweatherability compared with the following organic pigments.

As an organic pigment, the material may also include dark-colored azopigments, perylene black and aniline black. These have superiorweatherability compared with organic dyes. These materials also littleabsorb light of 780 nm or more in wavelength and transmit the same, andhence the visible light absorbing film in which any of these materialsis used can effectively transmits the light of 780 nm or more inwavelength to effectively utilize metallic reflection of the light of780 nm or more in wavelength. Then, it has been ascertained that such avisible light absorbing film has a better transmittance for the light of780 nm or more in wavelength than a case in which the inorganic materialis used, and hence has superior heat insulating properties when thevisible light absorbing film is formed on the metal vacuum-depositedsurface.

As to average dispersed-particle diameter the fine particles of any ofthese materials may have when dispersed in a liquid to make up thevisible light absorbing ink, it may preferably be 300 nm or less, andmore preferably be 100 nm or less. This is because fine particles ofmore than 300 nm or agglomerated particles having formed uponagglomeration may cause scattering of the light having wavelengths inthe visible region, in the visible light absorbing film having beenformed by coating, and can not provide the visible light absorbing filmwith any clear translucence to make the film look misty, where the hazevalue measured according to JIS K 7105 may come higher than the hazevalue of the substrate before coating and its gain may come to +3% ormore (for example, where the haze value of the substrate before coatingis a %, the haze value of the substrate after coating is a %+3% ormore). A problem may also arise such that no sharp color development isachievable. Another problem may further arise such that, if the fineparticles have an average dispersed-particle diameter of more than 300nm, the fine particles themselves may so strongly agglomerate as tocause, e.g., the settling of fine particles. Incidentally, the averagedispersed-particle diameter of the fine particles indicates an averagevalue of fine-particle particle diameters determined by means of anelectrophoresis light scattering photometer that utilizes the principleof a dynamic light scattering method.

As a method for dispersing the above material, any method may beselected as desired, as long as it is a method by which the fineparticles are uniformly dispersed in a solution. For example, availableare methods making use of a ball mill, a sand mill, ultrasonicdispersion, a medium agitation mill and the like.

To retain the state that the fine particles of the above material arekept dispersed stably in a liquid is also important in order to retainthe transparency required when the fine particles are mixed with abinder and thereafter the visible light absorbing film is formed. Then,as a method for evaluating a dispersion, a standard may be exemplifiedin which the haze value (measured according to JIS K 7105) of atransparent PET (polyethylene terephthalate) film is 3% or less after avisible light absorbing film has been formed thereon which has been socontrolled as to have a visible light transmittance of from 40% to 60%,in respect of the layer thickness of a visible light absorbing filmformed by coating on a 25 μm thick transparent PET (polyethyleneterephthalate) film a visible light absorbing ink prepared by mixing abinder component in an amount 10 times the weight of the fine particles.If this haze value is more than 3%, the fine particles may be dispersedin a poor state, and the fine particles themselves may so stronglyagglomerate as to cause the settling of fine particles. Further, a poortransparency may result when the fine particles are mixed with a binderand thereafter the visible light absorbing film is formed. Accordingly,the haze value of the transparent PET (polyethylene terephthalate) filmmay preferably be 3% or less after the visible light absorbing film hasbeen formed thereon which has been so controlled as to have a visiblelight transmittance of from 40% to 60%, in respect of the layerthickness of a visible light absorbing film formed by coating thevisible light absorbing ink on a 25 μm thick transparent PET(polyethylene terephthalate) film.

Incidentally, the above numerical value (40% to 60%) of the visiblelight transmittance in the visible light absorbing film is a numericalvalue given as an example employed in the method for evaluating adispersion, and this does not mean that the visible light transmittanceof the visible light absorbing film according to the present inventionis limited to the range of this numerical value.

In the visible light absorbing film according to the present invention,as described above, the degree of reduction of visible light reflectanceis set to 0.9 or less as defined by degree of reduction of visible lightreflectance=[visible light reflectance (%) after coating of theink]/[visible light reflectance (%) before coating of the ink], and thedegree of reduction of solar radiation reflectance is set to 0.25 ormore as defined by degree of reduction of solar radiationreflectance=[solar radiation reflectance (%) after coating of theink]/[solar radiation reflectance (%) before coating of the ink]. Thereason therefor is that, if the degree of reduction of visible lightreflectance is more than 0.9, the visible light absorbing film mayinsufficiently be effective in reducing the glaringness in the visibleregion, and also, if the degree of reduction of solar radiationreflectance is less than 0.25, the reflection efficiency for solarradiation heat may come so low as to result in poor heat insulatingproperties.

As the binder, usable are a ultraviolet curable resin, an electron raycurable resin, a thermoplastic resin, a thermosetting resin and thelike. There are no particular limitations on the types of these binders.The binder may also be used in the state it is mixed with the visiblelight absorbing ink or the fine particles may directly be mixed with thebinder to prepare the visible light absorbing ink so that it mayproperly be used according to its uses and purposes. It may also be usedin the state it is mixed with an adhesive with which films and so forthare bonded.

As the substrate, any desired material may be used as long as it hassolar radiation reflecting properties and has a visible lightreflectance of 10% or more, and may be exemplified by films, glasssheets, transparent resin sheets and so forth having such reflectioncharacteristics alone, films, glass sheets, transparent resin sheets andso forth on which metallic thin films of Al, Ag, Cu or the like havebeen formed, and composite members obtained by laminating the films,glass sheets, transparent resin sheets and so forth on which metallicthin films have been formed, to different films, glass sheets,transparent resin sheets and so forth.

In the film on which the metallic thin film is to be formed, thetransparent substrate may typically include PET film. Any resin filmsmay be selected which are suitable according to use purposes. Ingeneral, it is suitable to use clear resins having light transmissionproperties and less causative of light scattering, which may include, inrough classification, polycarbonate resins, polyacrylate or-methacrylate resins, cyclic olefin resins, saturated polyester resins,polystyrene, polyvinyl chloride and polyvinyl acetate. These transparentresin films may also be those having been subjected to surface treatmentaiming at an improvement in integrity to resin binders. As typicalmethods for such treatment, well known are corona treatment, plasmatreatment, flame treatment, primer layer coating treatment and so forth.Also, where these resin films are used for purposes where importance isattached to design quality, substrates may also be used which havebeforehand been templated. In order to stick these resin films to glassor the like, those to one sides of which an adhesive and a release filmhave been laminated may also be used. In this adhesive, the visiblelight absorbing ink according to the present invention may also bemixed. To this adhesive, an ultraviolet shielding agent may also beadded so that films or coating films can be prevented from undergoingultraviolet deterioration. Such an ultraviolet shielding agent mayinclude benzophenone ultraviolet absorbers and benzotriazole ultravioletabsorbers, as well as CeO₂, TiO₂ and ZnO. A hard coat layer may also beprovided at the outermost layer of any of these films, and a filmcapable of relatively readily softening upon heating with a dryer or thelike may also be used as the substrate so that it is convenient for itssticking to curved surfaces like those of rear windows of automobiles.

As a binder used to form a coating film such as the hard coat layer onthe resin film, an ultraviolet curable resin is well known in the art.It is typically composed of, as a chief component, a mixture of aphotopolymerizable oligomer such as epoxy acrylate, urethane acrylate,polyester acrylate or polyether acrylate and a photopolymerizablemonomer such as a monofunctional acrylate or a polyfunctional acrylate,and added thereto a photopolymerization initiator of a benzoin type, anacetophenone type, a thioxanthone type, a peroxide type or the like anda photopolymerization assistant initiator of an amine type, a quinonetype or the like. A heat polymerization inhibitor, an adhesion provider,a thixotropy provider, a plasticizer and a non-reactive polymer mayfurther be added. The above fine particles of the visible lightabsorbing material may also directly be dispersed in the ultravioletcurable resin, or may be mixed with a dispersion of the visible lightabsorbing material. The same effect is obtainable also when the visiblelight absorbing ink according to the present invention is mixed in theadhesive as described previously.

Fine particles of SiO₂, TiO₂, ZrO₂, Al₂O₃ or MgO may be added to thisultraviolet curable binder to more improve film strength. The sameeffect is obtainable also when inorganic matter such as SiO₂, TiO₂,ZrO₂, Al₂O₃ or MgO is chemically attached to the chief component of theultraviolet curable resin. The use of a ultraviolet curable-resin withsuperior properties such as wear resistance as a binder component of thevisible light absorbing ink according to the present invention makes itpossible to provide the resin film or resin substrate simultaneouslywith the property to selectively absorb the visible-region light and thewear resistance.

There are no particular limitations on a dispersion medium of thevisible light absorbing material (i.e., a solvent of the visible lightabsorbing ink), which may be selected in conformity with coatingconditions, coating environment, synthetic resin binders in inks, metalalkoxides and so forth. For example, usable are water and various kindsof organic solvents such as alcohols, ethers, esters and ketones. Also,as described above, the fine particles of the visible light absorbingmaterial may directly be dispersed in the binder component. For example,where a synthetic resin binder is used, the fine particles may directlybe dispersed in the resin so as to make up solvent-free ink compositionthat is gentle with environment. An acid or an alkali may alsooptionally be added to adjust the pH. Every kind of surface-activeagent, coupling agent and so forth may further be added in order toimprove dispersion stability of the visible light absorbing material inthe ink.

There are no particular limitations on methods for coating the visiblelight absorbing ink, and any method may be used as long as it is amethod by which the ink can smoothly and thinly uniformly be coated, asexemplified by dipping, flow coating, spray coating, bar coating, spincoating, gravure coating, roll coating, screen printing and bladecoating.

In the case when the synthetic resin binder is used, it may be curedaccording to a curing method for each resin. For example, in the case ofthe ultraviolet curable resin, an ultraviolet lamp may be selected inconformity with resonance wavelengths of the photopolymerizationinitiator for each resin and the intended curing rate. As a typicallamp, it may include low-pressure mercury lamps, high-pressure mercurylamps, ultrahigh-pressure mercury lamps, metal halide lamps, pulse xenonlamps, and electrodeless discharge lamps. Also, in the case of the resinbinder of an electron ray curable type, which makes use of nophotopolymerization initiator, an electron ray irradiator of a scanningtype, an electron curtain type or the like may be used to effect curing.Still also, in the case of a heat curable resin, it may be heated at theintended temperature.

Where the visible light absorbing ink according to the present inventionis mixed with the binder such as the ultraviolet curable resin and themixture obtained is coated on the surface of the substrate such as PETfilm, any desired film constitution may be employed in accordance withpurposes or production steps, without any particular limitations. Also,as to the layer thickness of the visible light absorbing film formedusing the visible light absorbing ink, which is influenced by thesubstrate and the properties of the binder resin, even a layer thicknessof 1 μm or less is sufficiently effective, and also, in making the layerthickness larger, the properties of the resin and substrate used serveas the standard by which its upper limit is determined.

The present invention is described below in greater detail by givingExamples.

Here, optical measurement in each Example and Comparative Example givenbelow is made according to JIS S 3107 (light source: D65). As thesubstrate, an Al vacuum-deposited semitransparent PET film (EMI-10,available from MIRAREED Corporation; PET film thickness: 25 μm) wasused, where the visible light absorbing ink was coated on one side orboth sides of the PET film and also this was stuck to a 3 mm thicktransparent float glass sheet to make optical measurement.

As to reflection measurements shown in Table 1, measurement was made ona case in which light was made incident on the surface of the film stuckand a case in which light was made incident on the glass side. As to thevisible light transmittance and solar radiation transmittance, eachtransmittance was measured on the case in which light was made incidenton the film surface.

In Table 1, the degree of reduction of visible light reflectance is avalue defined by degree of reduction of visible lightreflectance=[visible light reflectance (%) of each Example]/[visiblelight reflectance according to Comparative Example before coating of thevisible light absorbing ink, i.e., 52.1 or 53.4 (%)], and is an indexshowing the extent to which the visible light reflectance has lowered.The value of 0.9 or less is regarded as being acceptable.

In Table 1, the degree of reduction of solar radiation reflectance isalso a value defined by degree of reduction of solar radiationreflectance=[solar radiation reflectance (%) of each Example]/[solarradiation reflectance according to Comparative Example before coating ofthe visible light absorbing ink, i.e., 55.3 or 51.9 (%)], and is anindex showing the extent to which the solar radiation reflectance haslowered. The value of 0.25 or more is regarded as being acceptable. Thatis, a case of less than 0.25 shows that the solar radiation reflectancehas too lowered, and shows that the reflection of light havingwavelengths in the near infrared region and infrared region is small inthe visible light absorbing film.

The haze value was measured according to JIS K 7105. In Table 2, thelevel of change in haze value is a value found by subtracting the hazevalue before coating (the haze value of 3.1 in Comparative Example) fromthe haze value after coating of the visible light absorbing ink. Then, aminus value shows that the haze has improved after the visible lightabsorbing ink has been coated.

The chromaticness c*=[(a*)²+(b*)²]/^(1/2) in the L*a*b* color system wasalso measured according to JIS Z 8729 (light source: D65). The resultsare shown in Table 3. Incidentally, a chromaticness c* of 40 or less isregarded as being acceptable.

EXAMPLE 1

10 parts by weight of a Cu—Fe—Mn compound oxide (trade name: TMB #3550;available from Dainichiseika Color & Chemicals Mfg. Co., Ltd.) as avisible light absorbing material, 3 parts by weight of an ionicsurface-active agent for stabilizing dispersion and 80 parts by weightof toluene as a solvent were mixed.

The liquid mixture obtained was subjected to dispersion treatment so asto have a filler average dispersed-particle diameter of 90 nm or less.

To the dispersion obtained, 100 parts by weight of an ultravioletcurable resin (trade name: ADEKA OPTOMER KR-567; available fromAsahidenka Kogyo K.K.) and 0.5 part by weight of a silicone typesurface-active agent for improving leveling at the time of coating wereadded, followed by stirring to obtain a coating fluid (i.e., a visiblelight absorbing ink).

This was coated in the intended layer thickness by means of a barcoater. As a substrate therefor, the above Al vacuum-depositedsemitransparent PET film given as Comparative Example was used. Thiscoated PET film was stuck to a glass sheet on the former's surface onthe side opposite to the coated surface, and its optical characteristicswere measured.

The optical characteristics measured are shown in Tables 1 to 3 below.

EXAMPLE 2

A sample was prepared in the same manner as in Example 1 except that inplace of the above TMB #3550 a dark-colored azo pigment (trade name:CHROMOFINE BLACK A-1103; available from Dainichiseika Color & ChemicalsMfg. Co., Ltd.) was used. Its optical characteristics were alsomeasured.

The optical characteristics measured are shown in Tables 1 to 3 below.

EXAMPLE 3

The visible light absorbing ink prepared in Example 1 (TMB #3550) wascoated on a substrate, the above Al vacuum-deposited semitransparent PETfilm, and the visible light absorbing ink prepared in Example 2(CHROMOFINE BLACK A-1103) was coated on the back of this substrate. Thiscoated PET film was stuck to a glass sheet on the former's CHROMOFINEBLACK A-1103 ink surface, and its optical characteristics were measured.

The optical characteristics measured are shown in Tables 1 to 3 below.

EXAMPLE 4

A sample was prepared in the same manner as in Example 1 except that inplace of the above TMB #3550 a perylene type black pigment (trade name:PALIOGEN BLACK L 0086; available from BASF Corp.) was used. Its opticalcharacteristics were also measured.

The optical characteristics measured are shown in Tables 1 to 3 below.

EXAMPLE 5

A sample was prepared in the same manner as in Example 1 except that inplace of the above TMB #3550 an aniline type black pigment (trade name:PALIOTOL BLACK L 0080; available from BASF Corp.) was used. Its opticalcharacteristics were also measured.

The optical characteristics measured are shown in Tables 1 to 3 below.

EXAMPLE 6

A sample was prepared in the same manner as in Example 1 except that inplace of the above TMB #3550 a Cu—Cr—Mn compound oxide (trade name: TMB#3510; available from Dainichiseika Color & Chemicals Mfg. Co., Ltd.)was used. Its optical characteristics were also measured.

The optical characteristics measured are shown in Tables 1 to 3 below.

EXAMPLE 7

A sample was prepared in the same manner as in Example 1 except that inplace of the above TMB #3550 titanium black (trade name: TILACK-D;available from Ako Kasei Co., Ltd.) was used. Its opticalcharacteristics were also measured.

The optical characteristics measured are shown in Tables 1 to 3 below.

EXAMPLE 8

A sample was prepared in the same manner as in Example 1 except that inplace of the above TMB #3550 titanium nitride was used. Its opticalcharacteristics were also measured.

The optical characteristics measured are shown in Tables 1 to 3 below.

EXAMPLE 9

A sample was prepared in the same manner as in Example 1 except that inplace of the above TMB #3550 titanium oxynitride was used. Its opticalcharacteristics were also measured.

The optical characteristics measured are shown in Tables 1 to 3 below.

EXAMPLE 10

A sample was prepared in the same manner as in Example 1 except that inplace of the above TMB #3550 carbon black (trade name: CARBON BLACK#2650; available from Tokai Carbon Co., Ltd.) was used. Its opticalcharacteristics were also measured.

The optical characteristics measured are shown in Tables 1 to 3 below.

EXAMPLE 11

A sample was prepared in the same manner as in Example 1 except that inplace of the above TMB #3550 a colored pigment (trade name: S0084;available from BASF Corp.) was used. Its optical characteristics werealso measured.

The optical characteristics measured are shown in Tables 1 to 3 below.

COMPARATIVE EXAMPLE

On a 25 μm thick transparent PET film, Al was vacuum-deposited toprepare a transparent film having metallic luster (i.e., the above Alvacuum-deposited semitransparent PET film). Its optical characteristicsare shown in Tables 1 to 3 below. TABLE 1 Degree of Visible SolarVisible Solar reduction of: light radiation light radiation VisibleSolar Incident transmittance transmittance reflectance reflectance lightradiation on: (%) (%) (%) (%) reflectance reflectance ComparativeExample: F.surf. 19.2 15.5 52.1 55.3 — — G.surf. — — 53.4 51.9 — —Example: 1 F.surf. 10.7  9.9 18.9 28.7 0.36 0.52 G.surf. — — 52.6 51.1 —— 2 F.surf. 10.6 11.7 17.4 39.1 0.33 0.71 G.surf. — — 53.5 52.0 — — 3F.surf.  2.1  4.1  7.1 15.2 0.14 0.27 G.surf. — — 16.8 34.9 0.31 0.67 4F.surf.  8.7  9.6 13.8 32.2 0.26 0.58 G.surf. — — 53.4 52.1 — — 5F.surf. 11.0 11.0 18.2 32.9 0.35 0.60 G.surf. — — 53.3 51.8 — — 6F.surf. 11.2  9.8 20.4 27.8 0.39 0.50 G.surf. — — 53.1 51.8 — — 7F.surf. 12.2  8.9 23.0 20.1 0.44 0.36 G.surf. — — 53.2 51.8 — — 8F.surf. 12.4 10.5 24.6 29.7 0.47 0.54 G.surf. — — 53.2 51.9 — — 9F.surf. 11.7  9.2 20.1 21.4 0.39 0.39 G.surf. — — 53.3 51.8 — — 10F.surf. 11.8 10.3 23.4 30.9 0.45 0.56 G.surf. — — 53.0 51.7 — — 11F.surf.  8.2 12.4 12.5 36.4 0.24 0.66 G.surf. — — 53.3 52.1 — —F.surf.: Film surfaceG.surf.: Glass surface

TABLE 2 Haze Level of change value in haze value Incident on: (%) (%)Comparative Film surface 3.1 — Example: Example:  1 Film surface 2.5−0.6  2 Film surface 2.9 −0.2  3 Film surface 2.8 −0.3  4 Film surface3.0 −0.1  5 Film surface 2.6 −0.5  6 Film surface 2.2 −0.9  7 Filmsurface 2.4 −0.7  8 Film surface 2.6 −0.5  9 Film surface 2.3 −0.8 10Film surface 2.3 −0.8 11 Film surface 3.0 −0.1

TABLE 3 Color System (D65 Light Source, 10° Visual Field) Measurementconditions c* Example:  1 Film surface incident transmitted light 9.0Film surface incident reflected light 4.5  2 Film surface incidenttransmitted light 16.5 Film surface incident reflected light 9.4  3 Filmsurface incident transmitted light 9.2 Film surface incident reflectedlight 0.3 Glass surface incident reflected light 9.7  4 Film surfaceincident transmitted light 10.6 Film surface incident reflected light14.5  5 Film surface incident transmitted light 11.5 Film surfaceincident reflected light 0.8  6 Film surface incident transmitted light8.9 Film surface incident reflected light 5.1  7 Film surface incidenttransmitted light 13.0 Film surface incident reflected light 3.5  8 Filmsurface incident transmitted light 16.7 Film surface incident reflectedlight 7.9  9 Film surface incident transmitted light 14.8 Film surfaceincident reflected light 5.8 10 Film surface incident transmitted light6.1 Film surface incident reflected light 11.0 11 Film surface incidenttransmitted light 5.4 Film surface incident reflected light 11.3Comparative Example: Film surface incident transmitted light 13.0 Filmsurface incident reflected light 3.7 Glass surface incident reflectedlight 3.3

Confirmation

(1) As can be confirmed from numerical values (0.14 to 0.47) of Examplesshown in the column of “Degree of reduction of visible lightreflectance” in Table 1, the visible light reflectance has greatly beenreduced, compared with that of the Al vacuum-deposited semitransparentPET film according to Comparative Example on which no visible lightabsorbing film is formed, and it is confirmed that the glaringness isrestrained which is caused by the reflection of visible light from theAl vacuum-deposited semitransparent PET film according to each Exampleon which the visible light absorbing film is formed.

As can also be confirmed from numerical values (0.27 to 0.71) ofExamples shown in the column of “Degree of reduction of solar radiationreflectance” in Table 1, the degree of reduction of the same is 0.25 ormore, and it is also confirmed that the heat insulating properties ofthe Al vacuum-deposited semitransparent PET film according to eachExample on which the visible light absorbing film is formed cansufficiently function.

(2) Next, as can be confirmed from numerical values (−0.9 to −0.1) ofExamples shown in the column of “Level of change in haze value” in Table2, the haze value as well has greatly been improved, compared with thatof the Al vacuum-deposited semitransparent PET film according toComparative Example on which no visible light absorbing film is formed,and it is confirmed that the clear translucency of the Alvacuum-deposited semitransparent PET film according to each Example onwhich the visible light absorbing film is formed is also maintained.

(3) Further, as can be confirmed from numerical values of Examples shownin the column of chromaticness “c*” in Table 3, it is confirmed that, inthe Al vacuum-deposited semitransparent PET film according to eachExample, the color tone by no means comes too bright even where thevisible light absorbing film is formed.

POSSIBILITY OF INDUSTRIAL APPLICATION

As described hereinbefore, according to the visible light absorbing filmaccording to the present invention, having been formed on one side orboth sides of the substrate which has solar radiation reflectingproperties and whose visible light reflectance is 10% or more, and thestructural member having this visible light absorbing film, the degreeof reduction of visible light reflectance of the visible light absorbingfilm is 0.9 or less, and this reduces the reflection of visible lightfrom the substrate to enable restraint of glaringness in the visibleregion. Also, the degree of reduction of solar radiation reflectance is0.25 or more, and this retains the reflection of solar radiation fromthe substrate to enable the substrate to maintain even its heatinsulating properties. Hence, these can be utilized as heat rayreflection type heat insulating materials which are superior in bothdesign quality and heat insulating properties.

According to the visible light absorbing ink according to the presentinvention, the visible light absorbing film can be formed on one side orboth sides of the substrate which has solar radiation reflectingproperties and whose visible light reflectance is 10% or more. Hence,the ink can be utilized as a visible light absorbing ink when heat rayreflection type heat insulating materials are produced which aresuperior in both design quality and heat insulating properties.

1. A visible light absorbing film formed by a visible light absorbingink having been coated on one side or both sides of a substrate whichhas solar radiation reflecting properties and whose visible lightreflectance is 10% or more, characterized in that: the degree ofreduction of visible light reflectance is 0.9 or less as defined bydegree of reduction of visible light reflectance=[visible lightreflectance (%) after coating of the ink]/[visible light reflectance (%)before coating of the ink]; and the degree of reduction of solarradiation reflectance is 0.25 or more as defined by degree of reductionof solar radiation reflectance=[solar radiation reflectance (%) aftercoating of the ink]/[solar radiation reflectance (%) before coating ofthe ink].
 2. The visible light absorbing film according to claim 1,wherein, as a haze value measured according to JIS K 7105, saidsubstrate on which the visible light absorbing film has been formed hasa haze value which has been made lower than the haze value beforeformation of the visible light absorbing film, or the substrate on whichthe visible light absorbing film has been formed has a haze value whichhas been made higher than the haze value before formation of the visiblelight absorbing film and its gain is +3% or less.
 3. The visible lightabsorbing film according to claim 1, which has a value of 40 or less aschromaticness c*=[(a*)²+(b*)²]^(1/2) in the L*a*b* color system.
 4. Thevisible light absorbing film according to claim 1, wherein saidsubstrate is any of a film, a glass sheet and a transparent resin sheet,a film, a glass sheet and a transparent resin sheet on any of which ametallic thin film has been formed, and a composite member obtained bylaminating the film, the glass sheet and the transparent resin sheet onany of which a metallic thin film has been formed, to a different film,glass sheet or transparent resin sheet.
 5. The visible light absorbingfilm according to claim 1, wherein said substrate is a transparent filmon the surface of which a metallic thin film of Al, Ag or Cu has beenvacuum-deposited, or a composite member formed of the transparent filmon the surface of which the metallic thin film has been vacuum-depositedand a glass sheet.
 6. A structural member having a visible lightabsorbing film, characterized in that a laminate formed by providing thevisible light absorbing film according to claim 1, 2, 3, 4 or 5 on oneside or both sides of the substrate is incorporated directly or via anintervenient member or via a space.
 7. A visible light absorbing inkwhich forms the visible light absorbing film according to claim 1, 2, 3,4 or 5, characterized by containing at least one fine particles of acompound oxide selected from the group consisting of Cu—Fe—Mn, Cu—Cr,Cu—Cr—Mn, Cu—Cr—Mn—Ni, Cu—Cr—Fe and Co—Cr—Fe, titanium black, titaniumnitride, titanium oxynitride, a dark-colored azo pigment, a peryleneblack pigment, an aniline black pigment and carbon black; said fineparticles having an average dispersed-particle diameter of 300 nm orless in the ink.
 8. The visible light absorbing ink according to claim7, which is characterized by containing as a binder component at leastone inorganic high polymer, organic high polymer or inorganic-organiccomposite high polymer.